Oddities, musings and news from the health world

Rodent of the Week: Feeling less sick than you are

February 20, 2009 | 1:17
pm

"Sickness behavior" is a term used to describe people when they don't feel well. It's the fatigue, lethargy and loss of interest in life that accompanies a range of illnesses. It's that feeling you get when you can't get out of your jammies and all you can do is watch reruns on TV. You get the picture.

Now researchers writing in this week's issue of the Journal of Neuroscience say there may be a way to escape feeling sick -- even when you're sick. The scientists, from the University of Calgary, designed an experiment to understand why sickness behavior occurs when the brain is designed to be isolated from the immune system. Scientists have long wondered how the brain senses inflammation or injury in distant parts of the body. What they found, in a study of mice with liver disease, is that immune cells called monocytes infiltrate the brain. The liver inflammation triggers brain cells called microglia to produce a chemical that attracts monocytes, which are white blood cells. Further, the inflammation stimulates cells in the blood to make an immune chemical called TNFa. When the researchers blocked the signaling of TNFa in their experiment, however, microglia produced less of the chemical that attracts monocytes. What this meant for the sick mice is that they were more active and social. No reruns for these guys!

"Sickness behavior significantly impacts quality of life," said the lead author of the study, Dr. Mark Swain, in a news release. "Our findings further our understanding and may generate potential new avenues for treatment of these often crippling symptoms."